The present invention generally relates to aircraft armament apparatus and, in a preferred embodiment thereof, more particularly relates to apparatus and methods for operatively securing a weaponry support plank to the cabin area of a helicopter.
As representatively illustrated in U.S. Pat. No. 5,187,318 to Sanderson et al and U.S. Pat. No. 5,253,574 to Sanderson, an advantageous method of mounting weaponry, such as machine guns and rocket launchers, on a helicopter incorporates an elongated support plank member that is longitudinally extended transversely through the cabin area of the helicopter, with a central portion of the plank being anchored to the cabin area floor and outer end portions of the plank projecting outwardly beyond opposite sides of the helicopter. The selected weaponry is supported on the undersides of these outwardly projecting plank end portions.
As manufactured, the cabin area floor in the McDonnell Douglas 500/530 helicopter is strengthened by five forwardly disposed reinforcing ribs or "hats" riveted and spot welded to the top side of the floor. The ribs are in a mutually spaced, parallel array and longitudinally extend across the cabin area floor between opposite exterior sides of the helicopter. These ribs, while designed to strengthen the cabin area floor, are not strong enough under dynamic loading such as hang-fire loads, crash loads and gun recoil loads to support the weight of the plank and the weaponry secured to its outer ends, and must be reinforced to do so.
A previously used method of reinforcing the ribs, generally illustrated in the aforementioned U.S. Pat. Nos. 5,187,318 and 5,253,574, was to reinforce the forwardmost and rearwardmost rib by attaching relatively deep reinforcing beams to the opposite sides of each rib, parallel to their lengths, and securing transverse support members atop the opposite ends of the beams together with various auxiliary gussets and other bracing structures. The longitudinally intermediate plank portion was then mounted to top side portions of these transverse support members.
Three primary disadvantages were associated with this previously utilized plank-to-cabin floor securement technique. First, because of the height of the overall reinforcing structure, the cabin area floor became nearly unusable, even with the support plank removed. Second the relatively high weight (approximately 40 pounds) of the rib reinforcing structure and associated plank attachment apparatus was considered undesirable. Third, this previously utilized reinforcing structure tended to undesirably concentrate plank loading over a relatively small portion of the cabin area floor.
In view of the foregoing it can readily be seen that it would be desirable to provide improved apparatus and methods for operatively securing a longitudinally central weaponry support plank portion to a helicopter cabin area floor of the general type described above. It is accordingly an object of the present invention to provide such improved apparatus and methods.